Engines can produce highly audible tick noises. The frequency range of the tick noise may be in the range of several hundred Hz to 15.0 kHz. Interaction between the various components of the engine's valve train has been identified as a possible source of impact noises. A typical engine valve train may include a cam, tappet, valve retainer, valve stem, valve, valve coil spring, and a valve seat. Accordingly, one possible source of impact noise may include impact forces transferred from the tappet to the valve stem when the cam shaft lobe impacts the tappet. For example as the camshaft rotates and the cam lobe hits the tappet; the tappet may in turn hit the valve retainer fastened to the valve stem; the valve may then move to open the intake or exhaust to the combustion chamber. All these transient hits may emit high frequency tick noises from the various structural contacts and may transmit the noise through engine head/block and etc. to magnify tick noises. These tick noises may cover frequencies from 1000 Hz to 20,000 Hz.
Various attempts have been made to make valve train noises less audible. One attempt is disclosed in U.S. Pat. No. 4,563,984. The patent discloses a sleeve apparatus with a first sleeve fitted around an end of an intake pipe to absorb noise vibrations produced by combustion and by operation of the intake air control apparatus, i.e. valve train components, and a second sleeve encapsulating a fuel injection valve to absorb noise vibrations produced by pulsed fuel injection. The sleeve apparatus is located where the intake pipe is coupled with the cylinder head in order to prevent high-frequency pulse-like ticking noises from being reflected by the intake pipe.
The inventors herein have recognized several issues with this approach. For example, the approach only attempts to absorb and insulate the noises that are present and may not reduce the production of the noises.
Embodiments in accordance with the present disclosure may provide a valve train for an engine including a valve stem configured for reciprocating movement to open and close a port in a combustion chamber of the engine. The valve train may also include an elastomeric element coupled with the valve stem. A mass may be coupled with the elastomeric element and may be able to move relative to the valve stem.
Embodiments may include a valve retainer fixed to the valve stem. The elastomeric element may be an annular ring encircling at least a portion of the valve retainer. The mass may be an annular ring encircling at least a portion of the elastomeric element.
Some embodiments may provide a valve train for an engine including a valve stem of a valve movable to open and close a port to a combustion chamber of the engine. A mass may be coupled with the valve stem via a resilient member. In some cases the valve train may include a valve retainer fixed to the valve stem. The valve retainer may have an annular coupling surface. The resilient member may be an elastomeric ring fitted over the annular coupling surface and the mass may be an annular ring compressed over the elastomeric ring.
Some embodiments may provide a valve retainer including a coupling surface. An elastomeric element may be fixed to the coupling surface, and a mass may be over the elastomeric element.
In this way, the mass may tend to mitigate high frequency impact forces, and/or to absorb impact transient forces. In this way the production of noises from the valve train, in particular noises within particular frequency ranges, may be reduced.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.